1. Field of the Invention
The present invention relates generally to the packaging of electronic components. More particularly, the present invention relates to packaged electronic components and package mounting.
2. Description of the Related Art
Prior art methods and structures for packaging an electronic device, such as an integrated circuit, typically began with mounting the electronic device to a substrate. The substrate typically included conductive traces with bond pads formed on a top surface of the substrate. The prior art electronic devices were then attached to the conductive traces via the bond pads on the substrate using wire bonding, flip-chip, or various other well-known connection methods. The conductive traces on the top surface of the substrate were typically connected to solder ball pads on a bottom surface of the substrate by way of electrically conductive vias.
Once the prior art electronic device was attached to the substrate, the electronic device, and at least a portion of the substrate, were encased using various well know techniques including over molding, injection molding or by various other structures and/or methods.
According to the prior art, once the electronic device and substrate were attached and encased together, solder balls were formed on the solder ball pads on the bottom surface of the substrate. According to the prior art teachings, the solder balls formed on the bottom surface of the substrate were then re-flowed, i.e., re-melted, to attach the prior art packaged electronic device to attachment pads on a motherboard or other system component.
The prior art structure and method discussed above required not only the formation of solder balls on the bottom surface of the substrate, but also the re-flowing of the solder balls to either attach or remove the prior art packaged electronic device from the motherboard or other system component. This, in turn, meant that the installation and/or removal of prior art packaged electronic devices from the motherboard or other system component required special equipment and procedures. Consequently, the attachment and/or removal of prior art packaged electronic devices was difficult to perform in the field and relatively expensive.
In addition, the solder balls themselves used with prior art packaged electronic components were also expensive to form and required special equipment and procedures to make. The solder balls were also very fragile and very susceptible to environmental conditions and, in particular, change in temperature. In addition, the connections formed by the solder balls were also sensitive and easily broken. Thus, the solder balls used to connect prior art packaged electronic devices to motherboards or other system components were expensive to make, easily broken, and, to make matters worse, made the inevitable replacement of prior art packaged electronic devices difficult, time consuming and expensive.
What is needed is a simpler, less expensive, more reliable and more field accessible method and structure for connecting packaged electronic devices to a motherboard or larger system component.
In accordance with one embodiment of the present invention, a packaged electronic device includes an electronic device, such as an integrated circuit, electrically coupled to a substrate. In one embodiment of the invention, the substrate includes conductive traces with bond pads formed on a top, or first, surface of the substrate. According to one embodiment of the invention, the electronic devices are then attached to the conductive traces via the bond pads on the substrate using wire bonding, flip-chip, or various other well-known connection methods. In one embodiment of the invention, the conductive traces on the first surface of the substrate are connected to contact pads formed on a bottom, or second, surface of the substrate by way of electrically conductive vias.
According to one embodiment of the invention, once the electronic device is attached to the substrate, the electronic device, and at least a portion of the substrate, are encased using various well known techniques including over molding, injection molding or by various other structures and/or methods.
According to one embodiment of the invention, connection contacts are then formed on the contact pads on the second surface of the substrate. According to one embodiment of the invention, and in contrast to the prior art, the connection contacts are typically not solder contacts but are formed of hard metal or metal alloys such as nickel/aluminum plated copper and are therefore harder, less malleable and less subject to deformation than prior art solder balls.
In addition, according to one embodiment of the invention, and in contrast to the prior art, the connection contacts are not xe2x80x9cballsxe2x80x9d but are formed to have relatively wide bases at the contact pads and points on the opposite ends. In one embodiment of the invention, the connection contacts are formed to be substantially conical in shape with a relatively wide base at the contact pad and a relatively narrow point at the opposite end. In one embodiment of the invention, the connection contacts are formed to be substantially pyramid shaped with a relatively wide base at the contact pad and a relatively narrow point at the opposite end. In one embodiment of the invention, the connection contacts are formed to be substantially column shaped. In one embodiment of the invention, the connection contacts are formed to be substantially square or rectangular shaped. In one embodiment of the invention, the connection contacts are formed to be substantially spherical shaped or any other shape desired or considered advantageous in a particular structure.
According to one embodiment of the invention, the connection contacts formed on the contact pads of the second surface of the substrate of the packaged electronic device of the invention are formed to align with, and contact, attachment pads formed on a second system component such as a motherboard or other system component. In addition, according to one embodiment of the invention, the packaged electronic device of the invention includes a tension device for mechanically attaching, i.e., attaching by static pressure and friction, the packaged electronic device of the invention to the second system component. According to one embodiment of the invention, the tension device applies a pressure on the packaged electronic device and maintains contact between the connection contacts of the packaged electronic device of the invention and the attachment pads of the second system component or larger system component.
As discussed above, the prior art structures and methods required not only the formation of solder balls, but also the re-flowing of the solder balls to either attach or remove the prior art packaged electronic device from the second system component such as a motherboard or other system component. Consequently, the attachment and/or removal of prior art packaged electronic devices was difficult to perform in the field, relatively expensive and the electrical contacts so formed were unreliable, sensitive and easily broken.
In contrast, according to the invention, the packaged electronic devices are statically attached to the motherboard, or any other second system component, without the use of solder balls or the need to re-flow solder. Therefore, using the method and structure of the invention, there is no need for specialized equipment to attach or remove packaged electronic devices and these procedures can be performed easily in the field.
In addition, the electrical connection contacts of the invention are more rugged and less susceptible to environmental conditions than prior art structures and methods and therefore the method and structure of the invention allows for greater reliability and results in a more robust system. Consequently, the invention provides a simpler, less expensive, more reliable and more field accessible method and structure for connecting packaged. electronic devices to a motherboard or other second system component than the methods and structures of the prior art.